What is density of water? 64.4 Lb/ft3
What is value of g? 9.81 m/s2
What is relation between Density and Specific Weight? Specific weight shouldn’t be confused with density. P=density, slugs/ft3, g=acceleration due to gravity.
Define specific gravity? What is Specific gravity of water? The specific gravity is the ratio of the density of a substance to the total density of water, the specific gravity of water is 1.000 n/m3.
What is the Weight of 1.0 cubic foot of water? 62.4 lbs
What is specific gravity of Kerosene, which has a specific weight of 7.85 times 103 N/m3?
A reservoir of water is connected to a 12 in. diameter pipe 50 feet long and capped at the end. The water surface elevation of the reservoir is 82.5 ft and capped end of the pipe is at elevation 38 ft. Find the pressure in psf at the capped end of the pipe. 2776.8
The correct answer and explanation is:
Corrected Answer:
The pressure at the capped end of the pipe is 2671.2 psf.
Explanation:
To determine the pressure at the capped end of the pipe, we apply the hydrostatic pressure formula: P=γhP = \gamma h
where:
- PP = pressure at the capped end (psf)
- γ\gamma = specific weight of water (62.4 lb/ft³)
- hh = height difference between the water surface in the reservoir and the capped end (ft)
Step 1: Determine the height difference
h=82.5−38=44.5 fth = 82.5 – 38 = 44.5 \text{ ft}
Step 2: Calculate the pressure
P=(62.4 lb/ft3)×(44.5 ft)P = (62.4 \, \text{lb/ft}^3) \times (44.5 \, \text{ft}) P=2671.2 psfP = 2671.2 \, \text{psf}
Thus, the pressure at the capped end of the pipe is 2671.2 psf, not 2776.8 psf.
Understanding the Concept:
This calculation follows the principles of hydrostatic pressure, which states that pressure in a fluid at rest depends only on depth and density. Since the pipe is capped, there is no flow, and the pressure at the closed end is solely due to the column of water above it.
If the fluid were something other than water, we would need to adjust for its specific weight. Similarly, if the pipe had velocity, we would need to incorporate Bernoulli’s equation. However, in this static scenario, only hydrostatic pressure applies.
Now, generating an image to illustrate the problem.
Here is the diagram illustrating the hydrostatic pressure calculation. Let me know if you need any modifications or further clarifications!
